The most 'definitive' set of articles EVER
about tell-tales (where to place them and how to use them and how to 'trim' based on tell-tales) is found on www.arvelgentry.com ----> "magazine articles" ----> Checking Trim on the Wind, November 1973Achieving Proper Balance, December 1973Sailing to Windward, January 1974Are You at Optimum Trim?, March 1974These four 'articles' are a serialized 4 part offering of one long article that appeared in sail racing mags. This website also contains the seminal info on how sails really or actually work, etc. (not for the faint of heart) - dispells the 'slot effect', dispells the US high school and typical sailing instruction book ''CRAP" of how wings/sails work, etc. ... all based on aerodynamics.